The invention relates to the automatic sewing and/or joining of textiles, high polymer materials, leather and metals.
Technical solutions are known which make automatic sewing possible, wherein the sewing goods which are to joined, are guided along the seam point according to a desired geometric path. Two basic solutions prevail:
I. The sewing goods to be joined are rigidly clamped in a frame between plate chucks or similar elements, while the clamping element is moved underneath the seaming point according to the numerical web control.
Thus DE-OS No. 2629677 describes a numerically controlled sewing machine producing a seam in the sewing goods according to a sewing stencil. The innovation of this solution is that only a drawn stencil is handled by an optical scanning device with respective means, in such a manner that digital signals are obtained for the control of the stencil. Other devices (DE-OS No. 2313222 DD-WP No. 126881, U.S. Pat. No. 3,985,466, DE-OS No. 2826084 and U.S. Pat. No. 3,613,610) use punched tape or other recording carriers, carrying information. DE-OS No. 2557171 describes a device that accepts the sewing goods by a clamping device which photoelectrically scans the pre-basted edge of the sewing goods in the clamped position and thereby controls formation of an equidistant decorative strip.
II. The sewing goods to be joined are clamped either continuously or discontinuously in points and are guided under the seaming point with the aid of a guide edge and operating elements at suitable points for the transfer of the kinetic energy. Technical solutions according to this principle are described in DE-OS Nos. 2253990 and 2522422.
A series of technical solutions are known (DE-OS Nos. 2909664, 2907669, 2840048 and 2437777) which may be used according to their suitability, independent of the basic principle.
The disadvantage is that the known devices which rigidly clamp the sewing goods and guide the coordinated motions, although allowing a qualitatively perfect shape of the seam, require a high technical expense, for example a table which has to be moved following x- and y- coordinates.
The discontinuous sewing process is particularly disadvantageous because the sewing goods must be clamped onto the sewing goods carrier prior to sewing in front of the seaming point, and must be unfastened after sewing. This may only be improved by having a plurality of sewing goods carrriers in use, which increases the technical expense even more. The control of the motion of the sewing goods carrier occurs either in the traditional manner with the aid of stencils which are scanned either by mechanical, pneumatical or photo-electrical means or by being programmed with the aid of a CNC-control which controls the motional course of the drive elements of the sewing goods carrier.
The devices which guide the sewing goods with various elements under the seaming point without rigid clamping have the disadvantage that a deviation from the desired seam shape occurs between the drive elements for guiding and the seaming point due to the elastic nature of the sewing goods, and that the seam is reduced in quality. An additional disadvantage is that these devices mostly have a reduced field of application regarding the shape of the seam. The sewing machine cannot detect a deviation from the desired shape of the seam and cannot correct it.
The object of the invention is to automate the sewing process, to open new fields of use for automatic sewing, and to simultaneously improve the quality of the seam.
The economic effect is the saving of labor in the garment industry.